关于java UTF-8中文与Unicode编码之间转换，以及将浏览器地址栏编码过的中文转换UTF-8形式

1. 将浏览器地址栏编码过的中文转换回中文

    /**
 * @param fromStr : 要转换的原始字符串
 * @return : 得到转换后的字符串
 */
private String is(String fromStr) {
        StringBuffer stringBufferResult = new StringBuffer();
for (int i = 0; i < fromStr.length(); i++) {
char chr = fromStr.charAt(i);
if (chr == '%') {
                StringBuffer stringTmp = new StringBuffer();
                stringTmp.append(fromStr.charAt(i + 1)).append(fromStr.charAt(i + 2));
//转换字符，16进制转换成整型
                stringBufferResult.append((char) (Integer.valueOf(stringTmp.toString(), 16).intValue()));
                i = i + 2;
continue;
            }
            stringBufferResult.append(chr);
        }

        String newStr = null; //编码转换
try {
            newStr = new String(stringBufferResult.toString().getBytes("Cp1252"), "UTF-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
return newStr;
    }

2. 将字符串编码成 Unicode 形式的字符串与其反转换

 /**
 * 将字符串编码成 Unicode 形式的字符串. 如 "黄" to "\u9EC4"
 * Converts unicodes to encoded \\uxxxx and escapes
 * special characters with a preceding slash
 *
 * @param theString 待转换成Unicode编码的字符串。
 * @param escapeSpace 是否忽略空格，为true时在空格后面是否加个反斜杠。
 * @return 返回转换后Unicode编码的字符串。
 */
public static String toEncodedUnicode(String theString, boolean escapeSpace) {
int len = theString.length();
int bufLen = len * 2;
if (bufLen < 0) {
            bufLen = Integer.MAX_VALUE;
        }
        StringBuffer outBuffer = new StringBuffer(bufLen);
for (int x = 0; x < len; x++) {
char aChar = theString.charAt(x);
// Handle common case first, selecting largest block that
// avoids the specials below
if ((aChar > 61) && (aChar < 127)) {
if (aChar == '\\') {
                    outBuffer.append('\\');
                    outBuffer.append('\\');
continue;
                }
                outBuffer.append(aChar);
continue;
            }
switch (aChar) {
case ' ':
if (x == 0 || escapeSpace) outBuffer.append('\\');
                    outBuffer.append(' ');
break;
case '\t':
                    outBuffer.append('\\');
                    outBuffer.append('t');
break;
case '\n':
                    outBuffer.append('\\');
                    outBuffer.append('n');
break;
case '\r':
                    outBuffer.append('\\');
                    outBuffer.append('r');
break;
case '\f':
                    outBuffer.append('\\');
                    outBuffer.append('f');
break;
case '=': // Fall through
case ':': // Fall through
case '#': // Fall through
case '!':
                    outBuffer.append('\\');
                    outBuffer.append(aChar);
break;
default:
if ((aChar < 0x0020) || (aChar > 0x007e)) {
// 每个unicode有16位，每四位对应的16进制从高位保存到低位
                        outBuffer.append('\\');
                        outBuffer.append('u');
                        outBuffer.append(toHex((aChar >> 12) & 0xF));
                        outBuffer.append(toHex((aChar >> 8) & 0xF));
                        outBuffer.append(toHex((aChar >> 4) & 0xF));
                        outBuffer.append(toHex(aChar & 0xF));
                    } else {
                        outBuffer.append(aChar);
                    }
            }
        }
return outBuffer.toString();
    }
/**
 * 从 Unicode 形式的字符串转换成对应的编码的特殊字符串。 如 "\u9EC4" to "黄".
 * Converts encoded \\uxxxx to unicode chars
 * and changes special saved chars to their original forms
 *
 * @param in Unicode编码的字符数组。
 * @param off 转换的起始偏移量。
 * @param len 转换的字符长度。
 * @param in 转换的缓存字符数组。
 * @return 完成转换，返回编码前的特殊字符串。
 */
public static String fromEncodedUnicode(char[] in, int off, int len) {
char aChar;
char[] out = new char[len]; // 只短不长
int outLen = 0;
int end = off + len;
while (off < end) {
            aChar = in[off++];
if (aChar == '\\') {
                aChar = in[off++];
if (aChar == 'u') {
// Read the xxxx
int value = 0;
for (int i = 0; i < 4; i++) {
                        aChar = in[off++];
switch (aChar) {
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
                                value = (value << 4) + aChar - '0';
break;
case 'a':
case 'b':
case 'c':
case 'd':
case 'e':
case 'f':
                                value = (value << 4) + 10 + aChar - 'a';
break;
case 'A':
case 'B':
case 'C':
case 'D':
case 'E':
case 'F':
                                value = (value << 4) + 10 + aChar - 'A';
break;
default:
throw new IllegalArgumentException("Malformed \\uxxxx encoding.");
                        }
                    }
                    out[outLen++] = (char) value;
                } else {
if (aChar == 't') {
                        aChar = '\t';
                    } else if (aChar == 'r') {
                        aChar = '\r';
                    } else if (aChar == 'n') {
                        aChar = '\n';
                    } else if (aChar == 'f') {
                        aChar = '\f';
                    }
                    out[outLen++] = aChar;
                }
            } else {
                out[outLen++] = (char) aChar;
            }
        }
return new String(out, 0, outLen);
    }
private static final char[] hexDigit = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A',
'B', 'C', 'D', 'E', 'F'};
private static char toHex(int nibble) {
return hexDigit[(nibble & 0xF)];
    }